i2c-keywest.c

s3c2410上面的I2C驱动程序,直接insmod就可以用了

	/* State machine, to turn into an interrupt handler */
	while(iface->state != state_idle) {
		u8 isr = wait_interrupt(iface);
		handle_interrupt(iface, isr);
	}
#else /* POLLED_MODE */
	DBG("using interrupt mode...\n");
	wait_for_completion(&iface->complete);	
#endif /* POLLED_MODE */	

	rc = iface->result;	
	DBG("transfer done, result: %d\n", rc);

	if (rc == 0 && size == I2C_SMBUS_WORD_DATA && read_write == I2C_SMBUS_READ)
	    	data->word = le16_to_cpu(cur_word);
	
	/* Release sem */
	up(&iface->sem);
	
	return rc;
}

/*
 * Generic i2c master transfer entrypoint
 */
static int
keywest_xfer(	struct i2c_adapter *adap,
		struct i2c_msg msgs[], 
		int num)
{
	struct keywest_chan* chan = (struct keywest_chan*)adap->data;
	struct keywest_iface* iface = chan->iface;
	struct i2c_msg *pmsg;
	int i, completed;
	int rc = 0;

	down(&iface->sem);

	/* Set adapter to standard mode */
	iface->cur_mode &= ~KW_I2C_MODE_MODE_MASK;
	iface->cur_mode |= KW_I2C_MODE_STANDARD;

	completed = 0;
	for (i = 0; rc >= 0 && i < num;) {
		u8 addr;
		
		pmsg = &msgs[i++];
		addr = pmsg->addr;
		if (pmsg->flags & I2C_M_TEN) {
			printk(KERN_ERR "i2c-keywest: 10 bits addr not supported !\n");
			rc = -EINVAL;
			break;
		}
		DBG("xfer: chan: %d, doing %s %d bytes to 0x%02x - %d of %d messages\n",
		     chan->chan_no,
		     pmsg->flags & I2C_M_RD ? "read" : "write",
                     pmsg->len, addr, i, num);
    
		/* Setup channel & clear pending irqs */
		write_reg(reg_mode, iface->cur_mode | (chan->chan_no << 4));
		write_reg(reg_isr, read_reg(reg_isr));
		write_reg(reg_status, 0);
		
		iface->data = pmsg->buf;
		iface->datalen = pmsg->len;
		iface->state = state_addr;
		iface->result = 0;
		iface->stopretry = 0;
		if (pmsg->flags & I2C_M_RD)
			iface->read_write = I2C_SMBUS_READ;
		else
			iface->read_write = I2C_SMBUS_WRITE;

		/* Set up address and r/w bit */
		if (pmsg->flags & I2C_M_REV_DIR_ADDR)
			addr ^= 1;		
		write_reg(reg_addr,
			(addr << 1) |
			((iface->read_write == I2C_SMBUS_READ) ? 0x01 : 0x00));

		/* Arm timeout */
		iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
		add_timer(&iface->timeout_timer);

		/* Start sending address & enable interrupt*/
		write_reg(reg_control, read_reg(reg_control) | KW_I2C_CTL_XADDR);
		write_reg(reg_ier, KW_I2C_IRQ_MASK);

#ifdef POLLED_MODE
		DBG("using polled mode...\n");
		/* State machine, to turn into an interrupt handler */
		while(iface->state != state_idle) {
			u8 isr = wait_interrupt(iface);
			handle_interrupt(iface, isr);
		}
#else /* POLLED_MODE */88
		DBG("using interrupt mode...\n");
		wait_for_completion(&iface->complete);	
#endif /* POLLED_MODE */	

		rc = iface->result;
		if (rc == 0)
			completed++;
		DBG("transfer done, result: %d\n", rc);
	}

	/* Release sem */
	up(&iface->sem);

	return completed;
}

static u32
keywest_func(struct i2c_adapter * adapter)
{
	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
	       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
	       I2C_FUNC_SMBUS_BLOCK_DATA;
}

static void
keywest_inc(struct i2c_adapter *adapter)
{
	MOD_INC_USE_COUNT;
}

static void
keywest_dec(struct i2c_adapter *adapter)
{
	MOD_DEC_USE_COUNT;
}

/* For now, we only handle combined mode (smbus) */
static struct i2c_algorithm keywest_algorithm = {
	name:		"Keywest i2c",
	id:		I2C_ALGO_SMBUS,
	smbus_xfer:	keywest_smbus_xfer,
	master_xfer:	keywest_xfer,
	functionality:	keywest_func,
};


static int
create_iface(struct device_node* np)
{
	unsigned long steps, *psteps, *prate;
	unsigned bsteps, tsize, i, nchan, addroffset;
	struct keywest_iface* iface;
	int rc;

	psteps = (unsigned long *)get_property(np, "AAPL,address-step", NULL);
	steps = psteps ? (*psteps) : 0x10;

	/* Hrm... maybe we can be smarter here */
	for (bsteps = 0; (steps & 0x01) == 0; bsteps++)
		steps >>= 1;

	if (!strcmp(np->parent->name, "uni-n")) {
		nchan = 2;
		addroffset = 3;
	} else {
		addroffset = 0;
		nchan = 1;
	}

	tsize = sizeof(struct keywest_iface) +
		(sizeof(struct keywest_chan) + 4) * nchan;
	iface = (struct keywest_iface *) kmalloc(tsize, GFP_KERNEL);
	if (iface == NULL) {
		printk(KERN_ERR "i2c-keywest: can't allocate inteface !\n");
		return -ENOMEM;
	}
	memset(iface, 0, tsize);
	init_MUTEX(&iface->sem);
	spin_lock_init(&iface->lock);
	init_completion(&iface->complete);
	iface->bsteps = bsteps;
	iface->chan_count = nchan;
	iface->state = state_idle;
	iface->irq = np->intrs[0].line;
	iface->channels = (struct keywest_chan *)
		(((unsigned long)(iface + 1) + 3UL) & ~3UL);
	iface->base = (unsigned long)ioremap(np->addrs[0].address + addroffset,
						np->addrs[0].size);
	if (iface->base == 0) {
		printk(KERN_ERR "i2c-keywest: can't map inteface !\n");
		kfree(iface);
		return -ENOMEM;
	}

	init_timer(&iface->timeout_timer);
	iface->timeout_timer.function = keywest_timeout;
	iface->timeout_timer.data = (unsigned long)iface;

	/* Select interface rate */
	iface->cur_mode = KW_I2C_MODE_100KHZ;
	prate = (unsigned long *)get_property(np, "AAPL,i2c-rate", NULL);
	if (prate) switch(*prate) {
	case 100:
		iface->cur_mode = KW_I2C_MODE_100KHZ;
		break;
	case 50:
		iface->cur_mode = KW_I2C_MODE_50KHZ;
		break;
	case 25:
		iface->cur_mode = KW_I2C_MODE_25KHZ;
		break;
	default:
		printk(KERN_WARNING "i2c-keywest: unknown rate %ldKhz, using 100KHz\n",
			*prate);
	}
	
	/* Select standard sub mode */
	iface->cur_mode |= KW_I2C_MODE_STANDARDSUB;
	
	/* Write mode */
	write_reg(reg_mode, iface->cur_mode);
	
	/* Switch interrupts off & clear them*/
	write_reg(reg_ier, 0x00);
	write_reg(reg_isr, KW_I2C_IRQ_MASK);

#ifndef POLLED_MODE
	/* Request chip interrupt */	
	rc = request_irq(iface->irq, keywest_irq, 0, "keywest i2c", iface);
	if (rc) {
		printk(KERN_ERR "i2c-keywest: can't get IRQ %d !\n", iface->irq);
		iounmap((void *)iface->base);
		kfree(iface);
		return -ENODEV;
	}
#endif /* POLLED_MODE */

	for (i=0; i<nchan; i++) {
		struct keywest_chan* chan = &iface->channels[i];
		u8 addr;
		
		sprintf(chan->adapter.name, "%s %d", np->parent->name, i);
		chan->iface = iface;
		chan->chan_no = i;
		chan->adapter.id = I2C_ALGO_SMBUS;
		chan->adapter.algo = &keywest_algorithm;
		chan->adapter.algo_data = NULL;
		chan->adapter.inc_use = keywest_inc;
		chan->adapter.dec_use = keywest_dec;
		chan->adapter.client_register = NULL;
		chan->adapter.client_unregister = NULL;
		chan->adapter.data = chan;

		rc = i2c_add_adapter(&chan->adapter);
		if (rc) {
			printk("i2c-keywest.c: Adapter %s registration failed\n",
				chan->adapter.name);
			chan->adapter.data = NULL;
		}
		if (probe) {
			printk("Probe: ");
			for (addr = 0x00; addr <= 0x7f; addr++) {
				if (i2c_smbus_xfer(&chan->adapter,addr,
				    0,0,0,I2C_SMBUS_QUICK,NULL) >= 0)
					printk("%02x ", addr);
			}
			printk("\n");
		}
	}

	printk(KERN_INFO "Found KeyWest i2c on \"%s\", %d channel%s, stepping: %d bits\n",
		np->parent->name, nchan, nchan > 1 ? "s" : "", bsteps);
		
	iface->next = ifaces;
	ifaces = iface;
	return 0;
}

static void
dispose_iface(struct keywest_iface *iface)
{
	int i, rc;
	
	ifaces = iface->next;

	/* Make sure we stop all activity */
	down(&iface->sem);
#ifndef POLLED_MODE
	spin_lock_irq(&iface->lock);
	while (iface->state != state_idle) {
		spin_unlock_irq(&iface->lock);
		schedule();
		spin_lock_irq(&iface->lock);
	}
#endif /* POLLED_MODE */
	iface->state = state_dead;
#ifndef POLLED_MODE
	spin_unlock_irq(&iface->lock);
	free_irq(iface->irq, iface);
#endif /* POLLED_MODE */
	up(&iface->sem);

	/* Release all channels */
	for (i=0; i<iface->chan_count; i++) {
		struct keywest_chan* chan = &iface->channels[i];
		if (!chan->adapter.data)
			continue;
		rc = i2c_del_adapter(&chan->adapter);
		chan->adapter.data = NULL;
		/* We aren't that prepared to deal with this... */
		if (rc)
			printk("i2c-keywest.c: i2c_del_adapter failed, that's bad !\n");
	}
	iounmap((void *)iface->base);
	kfree(iface);
}

static int __init
i2c_keywest_init(void)
{
	struct device_node *np;
	int rc = -ENODEV;
	
	np = find_compatible_devices("i2c", "keywest");
	while (np != 0) {
		if (np->n_addrs >= 1 && np->n_intrs >= 1)
			rc = create_iface(np);
		np = np->next;
	}
	if (ifaces)
		rc = 0;
	return rc;
}

static void __exit
i2c_keywest_cleanup(void)
{
	while(ifaces)
		dispose_iface(ifaces);
}

module_init(i2c_keywest_init);
module_exit(i2c_keywest_cleanup);